Pulsatilla nigricans, commonly known as pulsatilla, is a remedy derived from the plant commonly known as wind flower, pasque flower, or meadow anemone. The perennial plant is a member of the Ranunculaceae family and is native to central and northern Europe and southern England. This wild plant grows in sunny meadows, pastures, and fields.

A crown of leaves forms on the ground, from which a single flower grows in May and August. The stem reaches a height of about 6 in (15 cm) and has downy hairs that grow on it. The flower is colored dark violet-brown.

The plant was used medicinally during ancient times for eye ailments. During the 19th century, the Eclectic physicians and contemporaries of Samuel Hahnemann, the father of homeopathy, noted pulsatilla's use in the treatment of melancholy, swelling of the knees, and nervous system disorders. In ancient times it was used as an external remedy for ulcers and eye inflammation.

The plant contains lactones, saponins, anemone camphor, tannins, and a volatile oil. It is antispasmodic and antibacterial and acts on the nervous system. When chewed, a caustic substance contained in the plant burns the tongue and throat. When applied topically, it may cause blisters on the skin. Though not used as widely as it was in the 19th century, pulsatilla may be used to treat painful periods, insomnia, headaches, boils, ovarian pain, and asthma.